1
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Lucca C, Ferrari E, Shubassi G, Ajazi A, Choudhary R, Bruhn C, Matafora V, Bachi A, Foiani M. Sch9 S6K controls DNA repair and DNA damage response efficiency in aging cells. Cell Rep 2024; 43:114281. [PMID: 38805395 DOI: 10.1016/j.celrep.2024.114281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 04/10/2024] [Accepted: 05/10/2024] [Indexed: 05/30/2024] Open
Abstract
Survival from UV-induced DNA lesions relies on nucleotide excision repair (NER) and the Mec1ATR DNA damage response (DDR). We study DDR and NER in aging cells and find that old cells struggle to repair DNA and activate Mec1ATR. We employ pharmacological and genetic approaches to rescue DDR and NER during aging. Conditions activating Snf1AMPK rescue DDR functionality, but not NER, while inhibition of the TORC1-Sch9S6K axis restores NER and enhances DDR by tuning PP2A activity, specifically in aging cells. Age-related repair deficiency depends on Snf1AMPK-mediated phosphorylation of Sch9S6K on Ser160 and Ser163. PP2A activity in old cells is detrimental for DDR and influences NER by modulating Snf1AMPK and Sch9S6K. Hence, the DDR and repair pathways in aging cells are influenced by the metabolic tuning of opposing AMPK and TORC1 networks and by PP2A activity. Specific Sch9S6K phospho-isoforms control DDR and NER efficiency, specifically during aging.
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Affiliation(s)
- Chiara Lucca
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Elisa Ferrari
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
| | - Ghadeer Shubassi
- AtomVie Global Radiopharma Inc., 1280 Main Street W NRB-A316, Hamilton, ON L8S-4K1, Canada
| | - Arta Ajazi
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Ramveer Choudhary
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Christopher Bruhn
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Vittoria Matafora
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Angela Bachi
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Marco Foiani
- IFOM ETS - The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy; Istituto di Genetica Molecolare, CNR, Pavia, Italy.
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2
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Casari E, Pizzul P, Rinaldi C, Gnugnoli M, Clerici M, Longhese MP. The PP2A phosphatase counteracts the function of the 9-1-1 axis in checkpoint activation. Cell Rep 2023; 42:113360. [PMID: 38007689 DOI: 10.1016/j.celrep.2023.113360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 09/25/2023] [Accepted: 10/13/2023] [Indexed: 11/27/2023] Open
Abstract
DNA damage elicits a checkpoint response depending on the Mec1/ATR kinase, which detects the presence of single-stranded DNA and activates the effector kinase Rad53/CHK2. In Saccharomyces cerevisiae, one of the signaling circuits leading to Rad53 activation involves the evolutionarily conserved 9-1-1 complex, which acts as a platform for the binding of Dpb11 and Rad9 (referred to as the 9-1-1 axis) to generate a protein complex that allows Mec1 activation. By examining the effects of both loss-of-function and hypermorphic mutations, here, we show that the Cdc55 and Tpd3 subunits of the PP2A phosphatase counteract activation of the 9-1-1 axis. The lack of this inhibitory function results in DNA-damage sensitivity, sustained checkpoint-mediated cell-cycle arrest, and impaired resection of DNA double-strand breaks. This PP2A anti-checkpoint role depends on the capacity of Cdc55 to interact with Ddc1 and to counteract Ddc1-Dpb11 complex formation by preventing Dpb11 recognition of Ddc1 phosphorylated on Thr602.
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Affiliation(s)
- Erika Casari
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Paolo Pizzul
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Carlo Rinaldi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Marco Gnugnoli
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Michela Clerici
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milano, Italy.
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3
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Zhou FY, Waterman DP, Caban-Penix S, Memisoglu G, Eapen VV, Haber JE. Prolonged Cell Cycle Arrest in Response to DNA damage in Yeast Requires the Maintenance of DNA Damage Signaling and the Spindle Assembly Checkpoint. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.15.540538. [PMID: 37292675 PMCID: PMC10245577 DOI: 10.1101/2023.05.15.540538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cells evoke the DNA damage checkpoint (DDC) to inhibit mitosis in the presence of DNA double-strand breaks (DSBs) to allow more time for DNA repair. In budding yeast, a single irreparable DSB is sufficient to activate the DDC and induce cell cycle arrest prior to anaphase for about 12 to 15 hours, after which cells "adapt" to the damage by extinguishing the DDC and resuming the cell cycle. While activation of the DNA damage-dependent cell cycle arrest is well-understood, how it is maintained remains unclear. To address this, we conditionally depleted key DDC proteins after the DDC was fully activated and monitored changes in the maintenance of cell cycle arrest. Degradation of Ddc2 ATRIP , Rad9, Rad24, or Rad53 CHK2 results in premature resumption of the cell cycle, indicating that these DDC factors are required both to establish and to maintain the arrest. Dun1 is required for establishment, but not maintenance of arrest, whereas Chk1 is required for prolonged maintenance but not for initial establishment of the mitotic arrest. When the cells are challenged with 2 persistent DSBs, they remain permanently arrested. This permanent arrest is initially dependent on the continuous presence of Ddc2 and Rad53; however, after 15 hours both proteins become dispensable. Instead, the continued mitotic arrest is sustained by spindle-assembly checkpoint (SAC) proteins Mad1, Mad2, and Bub2 but not by Bub2's binding partner Bfa1. These data suggest that prolonged cell cycle arrest in response to 2 DSBs is achieved by a handoff from the DDC to specific components of the SAC. Furthermore, the establishment and maintenance of DNA damage-induced cell cycle arrest requires overlapping but different sets of factors.
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4
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Pai CC, Durley SC, Cheng WC, Chiang NY, Peters J, Kasparek T, Blaikley E, Wee BY, Walker C, Kearsey SE, Buffa F, Murray JM, Humphrey TC. Homologous recombination suppresses transgenerational DNA end resection and chromosomal instability in fission yeast. Nucleic Acids Res 2023; 51:3205-3222. [PMID: 36951111 PMCID: PMC10123110 DOI: 10.1093/nar/gkad160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 02/13/2023] [Accepted: 02/23/2023] [Indexed: 03/24/2023] Open
Abstract
Chromosomal instability (CIN) drives cell-to-cell heterogeneity, and the development of genetic diseases, including cancer. Impaired homologous recombination (HR) has been implicated as a major driver of CIN, however, the underlying mechanism remains unclear. Using a fission yeast model system, we establish a common role for HR genes in suppressing DNA double-strand break (DSB)-induced CIN. Further, we show that an unrepaired single-ended DSB arising from failed HR repair or telomere loss is a potent driver of widespread CIN. Inherited chromosomes carrying a single-ended DSB are subject to cycles of DNA replication and extensive end-processing across successive cell divisions. These cycles are enabled by Cullin 3-mediated Chk1 loss and checkpoint adaptation. Subsequent propagation of unstable chromosomes carrying a single-ended DSB continues until transgenerational end-resection leads to fold-back inversion of single-stranded centromeric repeats and to stable chromosomal rearrangements, typically isochromosomes, or to chromosomal loss. These findings reveal a mechanism by which HR genes suppress CIN and how DNA breaks that persist through mitotic divisions propagate cell-to-cell heterogeneity in the resultant progeny.
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Affiliation(s)
- Chen-Chun Pai
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Samuel C Durley
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Wei-Chen Cheng
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Nien-Yi Chiang
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Jennifer Peters
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Torben Kasparek
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Elizabeth Blaikley
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Boon-Yu Wee
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Carol Walker
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Stephen E Kearsey
- Department of Biology, University of Oxford, Zoology Research and Administration Building, Mansfield Road, Oxford OX1 3SZ, UK
| | - Francesca Buffa
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Johanne M Murray
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, SussexBN1 9RQ, UK
| | - Timothy C Humphrey
- MRC Oxford Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
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Biregeya J, Anjago WM, Pan S, Zhang R, Yang Z, Chen M, Felix A, Xu H, Lin Y, Nkurikiyimfura O, Abubakar YS, Wang Z, Tang W. Type 2C Protein Phosphatases MoPtc5 and MoPtc7 Are Crucial for Multiple Stress Tolerance, Conidiogenesis and Pathogenesis of Magnaporthe oryzae. J Fungi (Basel) 2022; 9:jof9010001. [PMID: 36675822 PMCID: PMC9863299 DOI: 10.3390/jof9010001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
Protein kinases and phosphatases catalyze the phosphorylation and dephosphorylation of their protein substrates, respectively, and these are important mechanisms in cellular signal transduction. The rice blast fungus Magnaporthe oryzae possesses 6 protein phosphatases of type 2C class, including MoPtc1, 2, 5, 6, 7 and 8. However, only very little is known about the roles of these phosphatases in filamentous fungi. Here in, we deployed genetics and molecular biology techniques to identify, characterize and establish the roles of MoPtc5 and MoPtc7 in M. oryzae development and pathogenicity. We found that during pathogen-host interaction, MoPTC7 is differentially expressed. Double deletion of MoPTC7 and MoPTC5 suppressed the fungal vegetative growth, altered its cell wall integrity and reduced its virulence. The two genes were found indispensable for stress tolerance in the phytopathogen. We also demonstrated that disruption of any of the two genes highly affected appressorium turgor generation and Mps1 and Osm1 phosphorylation levels. Lastly, we demonstrated that both MoPtc5 and MoPtc7 are localized to mitochondria of different cellular compartments in the blast fungus. Taken together, our study revealed synergistic coordination of M. oryzae development and pathogenesis by the type 2C protein phosphatases.
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Affiliation(s)
- Jules Biregeya
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wilfred M. Anjago
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shu Pan
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ruina Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zifeng Yang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Meilian Chen
- Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China
| | - Abah Felix
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Huxiao Xu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yaqi Lin
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Oswald Nkurikiyimfura
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yakubu Saddeeq Abubakar
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Department of Biochemistry, Ahmadu Bello University, Zaria 810103, Nigeria
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China
- Correspondence: (Z.W.); (W.T.)
| | - Wei Tang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Correspondence: (Z.W.); (W.T.)
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6
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Casari E, Gnugnoli M, Rinaldi C, Pizzul P, Colombo CV, Bonetti D, Longhese MP. To Fix or Not to Fix: Maintenance of Chromosome Ends Versus Repair of DNA Double-Strand Breaks. Cells 2022; 11:cells11203224. [PMID: 36291091 PMCID: PMC9601279 DOI: 10.3390/cells11203224] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/07/2022] [Accepted: 10/12/2022] [Indexed: 02/08/2023] Open
Abstract
Early work by Muller and McClintock discovered that the physical ends of linear chromosomes, named telomeres, possess an inherent ability to escape unwarranted fusions. Since then, extensive research has shown that this special feature relies on specialized proteins and structural properties that confer identity to the chromosome ends, thus allowing cells to distinguish them from intrachromosomal DNA double-strand breaks. Due to the inability of conventional DNA replication to fully replicate the chromosome ends and the downregulation of telomerase in most somatic human tissues, telomeres shorten as cells divide and lose this protective capacity. Telomere attrition causes the activation of the DNA damage checkpoint that leads to a cell-cycle arrest and the entering of cells into a nondividing state, called replicative senescence, that acts as a barrier against tumorigenesis. However, downregulation of the checkpoint overcomes this barrier and leads to further genomic instability that, if coupled with re-stabilization of telomeres, can drive tumorigenesis. This review focuses on the key experiments that have been performed in the model organism Saccharomyces cerevisiae to uncover the mechanisms that protect the chromosome ends from eliciting a DNA damage response, the conservation of these pathways in mammals, as well as the consequences of their loss in human cancer.
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Yam CQX, Lim HH, Surana U. DNA damage checkpoint execution and the rules of its disengagement. Front Cell Dev Biol 2022; 10:1020643. [PMID: 36274841 PMCID: PMC9582513 DOI: 10.3389/fcell.2022.1020643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
Chromosomes are susceptible to damage during their duplication and segregation or when exposed to genotoxic stresses. Left uncorrected, these lesions can result in genomic instability, leading to cells’ diminished fitness, unbridled proliferation or death. To prevent such fates, checkpoint controls transiently halt cell cycle progression to allow time for the implementation of corrective measures. Prominent among these is the DNA damage checkpoint which operates at G2/M transition to ensure that cells with damaged chromosomes do not enter the mitotic phase. The execution and maintenance of cell cycle arrest are essential aspects of G2/M checkpoint and have been studied in detail. Equally critical is cells’ ability to switch-off the checkpoint controls after a successful completion of corrective actions and to recommence cell cycle progression. Interestingly, when corrective measures fail, cells can mount an unusual cellular response, termed adaptation, where they escape checkpoint arrest and resume cell cycle progression with damaged chromosomes at the cost of genome instability or even death. Here, we discuss the DNA damage checkpoint, the mitotic networks it inhibits to prevent segregation of damaged chromosomes and the strategies cells employ to quench the checkpoint controls to override the G2/M arrest.
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Affiliation(s)
| | - Hong Hwa Lim
- A*STAR Singapore Immunology Network, Singapore, Singapore
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Uttam Surana
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Pharmacology, National University of Singapore, Singapore, Singapore
- *Correspondence: Uttam Surana,
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Pizzul P, Casari E, Gnugnoli M, Rinaldi C, Corallo F, Longhese MP. The DNA damage checkpoint: A tale from budding yeast. Front Genet 2022; 13:995163. [PMID: 36186482 PMCID: PMC9520983 DOI: 10.3389/fgene.2022.995163] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 08/30/2022] [Indexed: 11/30/2022] Open
Abstract
Studies performed in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe have led the way in defining the DNA damage checkpoint and in identifying most of the proteins involved in this regulatory network, which turned out to have structural and functional equivalents in humans. Subsequent experiments revealed that the checkpoint is an elaborate signal transduction pathway that has the ability to sense and signal the presence of damaged DNA and transduce this information to influence a multifaceted cellular response that is essential for cancer avoidance. This review focuses on the work that was done in Saccharomyces cerevisiae to articulate the checkpoint concept, to identify its players and the mechanisms of activation and deactivation.
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GlPP2C1 Silencing Increases the Content of Ganodermalingzhi Polysaccharide (GL-PS) and Enhances Slt2 Phosphorylation. J Fungi (Basel) 2022; 8:jof8090949. [PMID: 36135674 PMCID: PMC9506439 DOI: 10.3390/jof8090949] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/07/2022] [Accepted: 09/07/2022] [Indexed: 11/17/2022] Open
Abstract
Polysaccharides have attracted much attention in the food industry due to their diverse biological activities. To date, research on the mechanism of polysaccharide synthesis has mainly focused on the role of crucial enzymes in the polysaccharide synthesis pathway, but other genes that regulate polysaccharide synthesis have not been well explored. In this study, the GlPP2C1 gene, encoding a phosphoprotein type 2C phosphatase, was cloned, and PP2C-silenced strains (PP2C1i-1 and PP2C1i-3) were screened. Measurements of the polysaccharide content and cell wall tolerance revealed that GlPP2C1 silencing increased the polysaccharide content and enhanced cell wall resistance in Ganoderma lingzhi. The contents of intracellular polysaccharides (IPS), extracellular polysaccharides (EPS) and β-1,3-D-glucan in PP2C-silenced strains were increased by 25%, 33% and 36%, respectively, compared with those in the WT strains and strains transformed with an empty vector. Further mechanistic studies showed that GlPP2C1 silencing increased the content of Ganoderma lingzhi polysaccharides (GL-PS) through Slt2. In summary, this study revealed the mechanism through which protein phosphatase regulates GL-PS biosynthesis for the first time.
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James Sanford E, Bustamante Smolka M. A field guide to the proteomics of post-translational modifications in DNA repair. Proteomics 2022; 22:e2200064. [PMID: 35695711 PMCID: PMC9950963 DOI: 10.1002/pmic.202200064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 05/19/2022] [Accepted: 05/30/2022] [Indexed: 12/15/2022]
Abstract
All cells incur DNA damage from exogenous and endogenous sources and possess pathways to detect and repair DNA damage. Post-translational modifications (PTMs), in the past 20 years, have risen to ineluctable importance in the study of the regulation of DNA repair mechanisms. For example, DNA damage response kinases are critical in both the initial sensing of DNA damage as well as in orchestrating downstream activities of DNA repair factors. Mass spectrometry-based proteomics revolutionized the study of the role of PTMs in the DNA damage response and has canonized PTMs as central modulators of nearly all aspects of DNA damage signaling and repair. This review provides a biologist-friendly guide for the mass spectrometry analysis of PTMs in the context of DNA repair and DNA damage responses. We reflect on the current state of proteomics for exploring new mechanisms of PTM-based regulation and outline a roadmap for designing PTM mapping experiments that focus on the DNA repair and DNA damage responses.
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Key Words
- LC-MS/MS, technology, bottom-up proteomics, technology, signal transduction, cell biology
- phosphoproteomics, technology, post-translational modification analysis, technology, post-translational modifications, cell biology, mass spectrometry
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Affiliation(s)
- Ethan James Sanford
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Marcus Bustamante Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853,Corresponding author:
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11
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A DNA Replication Fork-centric View of the Budding Yeast DNA Damage Response. DNA Repair (Amst) 2022; 119:103393. [DOI: 10.1016/j.dnarep.2022.103393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 11/23/2022]
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12
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Sadeghi A, Dervey R, Gligorovski V, Labagnara M, Rahi SJ. The optimal strategy balancing risk and speed predicts DNA damage checkpoint override times. NATURE PHYSICS 2022; 18:832-839. [PMID: 36281344 PMCID: PMC7613727 DOI: 10.1038/s41567-022-01601-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Checkpoints arrest biological processes allowing time for error correction. The phenomenon of checkpoint override (also known as checkpoint adaptation, slippage, or leakage), during cellular self-replication is biologically critical but currently lacks a quantitative, functional, or system-level understanding. To uncover fundamental laws governing error-correction systems, we derived a general theory of optimal checkpoint strategies, balancing the trade-off between risk and self-replication speed. Mathematically, the problem maps onto the optimization of an absorbing boundary for a random walk. We applied the theory to the DNA damage checkpoint (DDC) in budding yeast, an intensively researched model checkpoint. Using novel reporters for double-strand DNA breaks (DSBs), we first quantified the probability distribution of DSB repair in time including rare events and, secondly, the survival probability after override. With these inputs, the optimal theory predicted remarkably accurately override times as a function of DSB numbers, which we measured precisely for the first time. Thus, a first-principles calculation revealed undiscovered patterns underlying highly noisy override processes. Our multi-DSB measurements revise well-known past results and show that override is more general than previously thought.
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Affiliation(s)
- Ahmad Sadeghi
- Laboratory of the Physics of Biological Systems, Institute of Physics, École polytechnique fÉdÉrale de Lausanne (EPFL), Lausanne, Switzerland
| | - Roxane Dervey
- Laboratory of the Physics of Biological Systems, Institute of Physics, École polytechnique fÉdÉrale de Lausanne (EPFL), Lausanne, Switzerland
| | - Vojislav Gligorovski
- Laboratory of the Physics of Biological Systems, Institute of Physics, École polytechnique fÉdÉrale de Lausanne (EPFL), Lausanne, Switzerland
| | - Marco Labagnara
- Laboratory of the Physics of Biological Systems, Institute of Physics, École polytechnique fÉdÉrale de Lausanne (EPFL), Lausanne, Switzerland
| | - Sahand Jamal Rahi
- Laboratory of the Physics of Biological Systems, Institute of Physics, École polytechnique fÉdÉrale de Lausanne (EPFL), Lausanne, Switzerland
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13
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Moriel-Carretero M. The Many Faces of Lipids in Genome Stability (and How to Unmask Them). Int J Mol Sci 2021; 22:12930. [PMID: 34884734 PMCID: PMC8657548 DOI: 10.3390/ijms222312930] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/12/2021] [Accepted: 11/26/2021] [Indexed: 12/15/2022] Open
Abstract
Deep efforts have been devoted to studying the fundamental mechanisms ruling genome integrity preservation. A strong focus relies on our comprehension of nucleic acid and protein interactions. Comparatively, our exploration of whether lipids contribute to genome homeostasis and, if they do, how, is severely underdeveloped. This disequilibrium may be understood in historical terms, but also relates to the difficulty of applying classical lipid-related techniques to a territory such as a nucleus. The limited research in this domain translates into scarce and rarely gathered information, which with time further discourages new initiatives. In this review, the ways lipids have been demonstrated to, or very likely do, impact nuclear transactions, in general, and genome homeostasis, in particular, are explored. Moreover, a succinct yet exhaustive battery of available techniques is proposed to tackle the study of this topic while keeping in mind the feasibility and habits of "nucleus-centered" researchers.
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Affiliation(s)
- María Moriel-Carretero
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, Centre National de la Recherche Scientifique, CEDEX 5, 34293 Montpellier, France
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14
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Yao S, Feng Y, Zhang Y, Feng J. DNA damage checkpoint and repair: From the budding yeast Saccharomyces cerevisiae to the pathogenic fungus Candida albicans. Comput Struct Biotechnol J 2021; 19:6343-6354. [PMID: 34938410 PMCID: PMC8645783 DOI: 10.1016/j.csbj.2021.11.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/16/2021] [Accepted: 11/20/2021] [Indexed: 01/09/2023] Open
Abstract
Cells are constantly challenged by internal or external genotoxic assaults, which may induce a high frequency of DNA lesions, leading to genome instability. Accumulation of damaged DNA is severe or even lethal to cells and can result in abnormal proliferation that can cause cancer in multicellular organisms, aging or cell death. Eukaryotic cells have evolved a comprehensive defence system termed the DNA damage response (DDR) to monitor and remove lesions in their DNA. The DDR has been extensively studied in the budding yeast Saccharomyces cerevisiae. Emerging evidence indicates that DDR genes in the pathogenic fungus Candida albicans show functional consistency with their orthologs in S. cerevisiae, but may act through distinct mechanisms. In particular, the DDR in C. albicans appears critical for resisting DNA damage stress induced by reactive oxygen species (ROS) produced from immune cells, and this plays a vital role in pathogenicity. Therefore, DDR genes could be considered as potential targets for clinical therapies. This review summarizes the identified DNA damage checkpoint and repair genes in C. albicans based on their orthologs in S. cerevisiae, and discusses their contribution to pathogenicity in C. albicans.
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Affiliation(s)
- Shuangyan Yao
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, Jiangsu, China
- Nantong Health College of Jiangsu Province, Nantong 226016, Jiangsu, China
| | - Yuting Feng
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, Jiangsu, China
| | - Yan Zhang
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, Jiangsu, China
| | - Jinrong Feng
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, Jiangsu, China
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15
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Licheva M, Raman B, Kraft C, Reggiori F. Phosphoregulation of the autophagy machinery by kinases and phosphatases. Autophagy 2021; 18:104-123. [PMID: 33970777 PMCID: PMC8865292 DOI: 10.1080/15548627.2021.1909407] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cells use post-translational modifications to diversify and dynamically coordinate the function and properties of protein networks within various cellular processes. For example, the process of autophagy strongly depends on the balanced action of kinases and phosphatases. Highly conserved from the budding yeast Saccharomyces cerevisiae to humans, autophagy is a tightly regulated self-degradation process that is crucial for survival, stress adaptation, maintenance of cellular and organismal homeostasis, and cell differentiation and development. Many studies have emphasized the importance of kinases and phosphatases in the regulation of autophagy and identified many of the core autophagy proteins as their direct targets. In this review, we summarize the current knowledge on kinases and phosphatases acting on the core autophagy machinery and discuss the relevance of phosphoregulation for the overall process of autophagy.
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Affiliation(s)
- Mariya Licheva
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Babu Raman
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Fulvio Reggiori
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
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16
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The Srs2 helicase dampens DNA damage checkpoint by recycling RPA from chromatin. Proc Natl Acad Sci U S A 2021; 118:2020185118. [PMID: 33602817 DOI: 10.1073/pnas.2020185118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The DNA damage checkpoint induces many cellular changes to cope with genotoxic stress. However, persistent checkpoint signaling can be detrimental to growth partly due to blockage of cell cycle resumption. Checkpoint dampening is essential to counter such harmful effects, but its mechanisms remain to be understood. Here, we show that the DNA helicase Srs2 removes a key checkpoint sensor complex, RPA, from chromatin to down-regulate checkpoint signaling in budding yeast. The Srs2 and RPA antagonism is supported by their numerous suppressive genetic interactions. Importantly, moderate reduction of RPA binding to single-strand DNA (ssDNA) rescues hypercheckpoint signaling caused by the loss of Srs2 or its helicase activity. This rescue correlates with a reduction in the accumulated RPA and the associated checkpoint kinase on chromatin in srs2 mutants. Moreover, our data suggest that Srs2 regulation of RPA is separable from its roles in recombinational repair and critically contributes to genotoxin resistance. We conclude that dampening checkpoint by Srs2-mediated RPA recycling from chromatin aids cellular survival of genotoxic stress and has potential implications in other types of DNA transactions.
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17
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Fedorov DV, Evstyukhina TA, Peshekhonov VT, Korolev VG. Pph3 Phosphatase Participates in the Regulation of the Error-Free Branch of Postreplication DNA Repair in Yeast Saccharomyces cerevisiae. RUSS J GENET+ 2021. [DOI: 10.1134/s1022795421010063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Stolarova L, Kleiblova P, Janatova M, Soukupova J, Zemankova P, Macurek L, Kleibl Z. CHEK2 Germline Variants in Cancer Predisposition: Stalemate Rather than Checkmate. Cells 2020; 9:cells9122675. [PMID: 33322746 PMCID: PMC7763663 DOI: 10.3390/cells9122675] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/04/2020] [Accepted: 12/10/2020] [Indexed: 12/15/2022] Open
Abstract
Germline alterations in many genes coding for proteins regulating DNA repair and DNA damage response (DDR) to DNA double-strand breaks (DDSB) have been recognized as pathogenic factors in hereditary cancer predisposition. The ATM-CHEK2-p53 axis has been documented as a backbone for DDR and hypothesized as a barrier against cancer initiation. However, although CHK2 kinase coded by the CHEK2 gene expedites the DDR signal, its function in activation of p53-dependent cell cycle arrest is dispensable. CHEK2 mutations rank among the most frequent germline alterations revealed by germline genetic testing for various hereditary cancer predispositions, but their interpretation is not trivial. From the perspective of interpretation of germline CHEK2 variants, we review the current knowledge related to the structure of the CHEK2 gene, the function of CHK2 kinase, and the clinical significance of CHEK2 germline mutations in patients with hereditary breast, prostate, kidney, thyroid, and colon cancers.
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Affiliation(s)
- Lenka Stolarova
- Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, Charles University, 12800 Prague, Czech Republic; (L.S.); (M.J.); (J.S.); (P.Z.)
- Laboratory of Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic;
| | - Petra Kleiblova
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic;
| | - Marketa Janatova
- Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, Charles University, 12800 Prague, Czech Republic; (L.S.); (M.J.); (J.S.); (P.Z.)
| | - Jana Soukupova
- Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, Charles University, 12800 Prague, Czech Republic; (L.S.); (M.J.); (J.S.); (P.Z.)
| | - Petra Zemankova
- Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, Charles University, 12800 Prague, Czech Republic; (L.S.); (M.J.); (J.S.); (P.Z.)
| | - Libor Macurek
- Laboratory of Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic;
| | - Zdenek Kleibl
- Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, Charles University, 12800 Prague, Czech Republic; (L.S.); (M.J.); (J.S.); (P.Z.)
- Correspondence: ; Tel.: +420-22496-745
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19
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Memisoglu G, Lanz MC, Eapen VV, Jordan JM, Lee K, Smolka MB, Haber JE. Mec1 ATR Autophosphorylation and Ddc2 ATRIP Phosphorylation Regulates DNA Damage Checkpoint Signaling. Cell Rep 2020; 28:1090-1102.e3. [PMID: 31340146 DOI: 10.1016/j.celrep.2019.06.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 02/21/2019] [Accepted: 06/18/2019] [Indexed: 11/26/2022] Open
Abstract
In budding yeast, a single DNA double-strand break (DSB) triggers the activation of Mec1ATR-dependent DNA damage checkpoint. After about 12 h, cells turn off the checkpoint signaling and adapt despite the persistence of the DSB. We report that the adaptation involves the autophosphorylation of Mec1 at site S1964. A non-phosphorylatable mec1-S1964A mutant causes cells to arrest permanently in response to a single DSB without affecting the initial kinase activity of Mec1. Autophosphorylation of S1964 is dependent on Ddc1Rad9 and Dpb11TopBP1, and it correlates with the timing of adaptation. We also report that Mec1's binding partner, Ddc2ATRIP, is an inherently stable protein that is degraded specifically upon DNA damage. Ddc2 is regulated extensively through phosphorylation, which, in turn, regulates the localization of the Mec1-Ddc2 complex to DNA lesions. Taken together, these results suggest that checkpoint response is regulated through the autophosphorylation of Mec1 kinase and through the changes in Ddc2 abundance and phosphorylation.
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Affiliation(s)
- Gonen Memisoglu
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Michael C Lanz
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Vinay V Eapen
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jacqueline M Jordan
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Kihoon Lee
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA; Seegene, Inc., Ogeum-ro, Songpa-gu, Seoul 05548, Korea
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA.
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20
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Vydzhak O, Bender K, Klermund J, Busch A, Reimann S, Luke B. Checkpoint adaptation in recombination-deficient cells drives aneuploidy and resistance to genotoxic agents. DNA Repair (Amst) 2020; 95:102939. [PMID: 32777450 DOI: 10.1016/j.dnarep.2020.102939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/21/2020] [Accepted: 07/21/2020] [Indexed: 11/19/2022]
Abstract
Human cancers frequently harbour mutations in DNA repair genes, rendering the use of DNA damaging agents as an effective therapeutic intervention. As therapy-resistant cells often arise, it is important to better understand the molecular pathways that drive resistance in order to facilitate the eventual targeting of such processes. We employ recombination-defective diploid yeast as a model to demonstrate that, in response to genotoxic challenges, nearly all cells eventually undergo checkpoint adaptation, resulting in the generation of aneuploid cells with whole chromosome losses that have acquired resistance to the initial genotoxic challenge. We demonstrate that adaptation inhibition, either pharmacologically, or genetically, drastically reduces the occurrence of resistant cells. Additionally, the aneuploid phenotypes of the resistant cells can be specifically targeted to induce cytotoxicity. We provide evidence that TORC1 inhibition with rapamycin, in combination with DNA damaging agents, can prevent both checkpoint adaptation and the continued growth of aneuploid resistant cells.
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Affiliation(s)
- Olga Vydzhak
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany; Johannes Gutenberg University Mainz, Faculty of Biology, Institute of Developmental Biology and Neurobiology, Mainz, 55128, Germany
| | - Katharina Bender
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany; Johannes Gutenberg University Mainz, Faculty of Biology, Institute of Developmental Biology and Neurobiology, Mainz, 55128, Germany
| | - Julia Klermund
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany
| | - Anke Busch
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany
| | - Stefanie Reimann
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany; Johannes Gutenberg University Mainz, Faculty of Biology, Institute of Developmental Biology and Neurobiology, Mainz, 55128, Germany
| | - Brian Luke
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany; Johannes Gutenberg University Mainz, Faculty of Biology, Institute of Developmental Biology and Neurobiology, Mainz, 55128, Germany.
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21
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Abstract
Cells confront DNA damage in every cell cycle. Among the most deleterious types of DNA damage are DNA double-strand breaks (DSBs), which can cause cell lethality if unrepaired or cancers if improperly repaired. In response to DNA DSBs, cells activate a complex DNA damage checkpoint (DDC) response that arrests the cell cycle, reprograms gene expression, and mobilizes DNA repair factors to prevent the inheritance of unrepaired and broken chromosomes. Here we examine the DDC, induced by DNA DSBs, in the budding yeast model system and in mammals.
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Affiliation(s)
- David P Waterman
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA;
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA;
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA;
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22
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Morafraile EC, Bugallo A, Carreira R, Fernández M, Martín-Castellanos C, Blanco MG, Segurado M. Exo1 phosphorylation inhibits exonuclease activity and prevents fork collapse in rad53 mutants independently of the 14-3-3 proteins. Nucleic Acids Res 2020; 48:3053-3070. [PMID: 32020204 PMCID: PMC7102976 DOI: 10.1093/nar/gkaa054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/15/2020] [Accepted: 01/20/2020] [Indexed: 01/04/2023] Open
Abstract
The S phase checkpoint is crucial to maintain genome stability under conditions that threaten DNA replication. One of its critical functions is to prevent Exo1-dependent fork degradation, and Exo1 is phosphorylated in response to different genotoxic agents. Exo1 seemed to be regulated by several post-translational modifications in the presence of replicative stress, but the specific contribution of checkpoint-dependent phosphorylation to Exo1 control and fork stability is not clear. We show here that Exo1 phosphorylation is Dun1-independent and Rad53-dependent in response to DNA damage or dNTP depletion, and in both situations Exo1 is similarly phosphorylated at multiple sites. To investigate the correlation between Exo1 phosphorylation and fork stability, we have generated phospho-mimic exo1 alleles that rescue fork collapse in rad53 mutants as efficiently as exo1-nuclease dead mutants or the absence of Exo1, arguing that Rad53-dependent phosphorylation is the mayor requirement to preserve fork stability. We have also shown that this rescue is Bmh1–2 independent, arguing that the 14-3-3 proteins are dispensable for fork stabilization, at least when Exo1 is downregulated. Importantly, our results indicated that phosphorylation specifically inhibits the 5' to 3'exo-nuclease activity, suggesting that this activity of Exo1 and not the flap-endonuclease, is the enzymatic activity responsible of the collapse of stalled replication forks in checkpoint mutants.
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Affiliation(s)
- Esther C Morafraile
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - Alberto Bugallo
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - Raquel Carreira
- Departamento de Bioquímica y Biología Molecular, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS) - Instituto de Investigación Sanitaria (IDIS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - María Fernández
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | | | - Miguel G Blanco
- Departamento de Bioquímica y Biología Molecular, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS) - Instituto de Investigación Sanitaria (IDIS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Mónica Segurado
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain.,Departamento de Microbiología y Genética, Campus Miguel de Unamuno, Universidad de Salamanca, Salamanca 37007, Spain
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23
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Villoria MT, Gutiérrez-Escribano P, Alonso-Rodríguez E, Ramos F, Merino E, Campos A, Montoya A, Kramer H, Aragón L, Clemente-Blanco A. PP4 phosphatase cooperates in recombinational DNA repair by enhancing double-strand break end resection. Nucleic Acids Res 2020; 47:10706-10727. [PMID: 31544936 PMCID: PMC6846210 DOI: 10.1093/nar/gkz794] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/30/2019] [Accepted: 09/11/2019] [Indexed: 12/30/2022] Open
Abstract
The role of Rad53 in response to a DNA lesion is central for the accurate orchestration of the DNA damage response. Rad53 activation relies on its phosphorylation by Mec1 and its own autophosphorylation in a manner dependent on the adaptor Rad9. While the mechanism behind Rad53 activation has been well documented, less is known about the processes that counteract its activity along the repair of a DNA adduct. Here, we describe that PP4 phosphatase is required to avoid Rad53 hyper-phosphorylation during the repair of a double-strand break, a process that impacts on the phosphorylation status of multiple factors involved in the DNA damage response. PP4-dependent Rad53 dephosphorylation stimulates DNA end resection by relieving the negative effect that Rad9 exerts over the Sgs1/Dna2 exonuclease complex. Consequently, elimination of PP4 activity affects resection and repair by single-strand annealing, defects that are bypassed by reducing Rad53 hyperphosphorylation. These results confirm that Rad53 phosphorylation is controlled by PP4 during the repair of a DNA lesion and demonstrate that the attenuation of its kinase activity during the initial steps of the repair process is essential to efficiently enhance recombinational DNA repair pathways that depend on long-range resection for their success.
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Affiliation(s)
- María Teresa Villoria
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Pilar Gutiérrez-Escribano
- Cell Cycle Group. Medical Research Council, London Institute of Medical Science, Du Cane Road, London W12 0NN, UK
| | - Esmeralda Alonso-Rodríguez
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Facundo Ramos
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Eva Merino
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Adrián Campos
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
| | - Alex Montoya
- Biological Mass Spectrometry and Proteomics Laboratory, Medical Research Council, London Institute of Medical Science, Du Cane Road, London W12 0NN, UK
| | - Holger Kramer
- Biological Mass Spectrometry and Proteomics Laboratory, Medical Research Council, London Institute of Medical Science, Du Cane Road, London W12 0NN, UK
| | - Luis Aragón
- Cell Cycle Group. Medical Research Council, London Institute of Medical Science, Du Cane Road, London W12 0NN, UK
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group, Institute of Functional Biology and Genomics (IBFG), Spanish National Research Council (CSIC). University of Salamanca (USAL), C/ Zacarías González 2, Salamanca 37007, Spain
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24
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Feng J, Islam A, Bean B, Feng J, Sparapani S, Shrivastava M, Goyal A, Omran RP, Mallick J, Whiteway M. Hof1 plays a checkpoint-related role in MMS-induced DNA damage response in Candida albicans. Mol Biol Cell 2020; 31:348-359. [PMID: 31940254 PMCID: PMC7183792 DOI: 10.1091/mbc.e19-06-0316] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cells depend on robust DNA damage recognition and repair systems to maintain genomic integrity for survival in a mutagenic environment. In the pathogenic yeast Candida albicans, a subset of genes involved in the response to DNA damage-induced genome instability and morphological changes has been found to regulate virulence. To better understand the virulence-linked DNA repair network, we screened for methyl methane sulfonate (MMS) sensitivity within the GRACE conditional expression collection and identified 56 hits. One of these potential DNA damage repair-associated genes, a HOF1 conditional mutant, unexpectedly had a previously characterized function in cytokinesis. Deletion of HOF1 resulted in MMS sensitivity and genome instability, suggesting Hof1 acts in the DNA damage response. By probing genetic interactions with distinct DNA repair pathways, we found that Hof1 is genetically linked to the Rad53 pathway. Furthermore, Hof1 is down-regulated in a Rad53-dependent manner and its importance in the MMS response is reduced when Rad53 is overexpressed or when RAD4 or RAD23 is deleted. Together, this work expands our understanding of the C. albicans DNA repair network and uncovers interplay between the cytokinesis regulator Hof1 and the Rad53-mediated checkpoint.
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Affiliation(s)
- Jinrong Feng
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong, Jiangsu 226001, China
| | - Amjad Islam
- Biology Department, Concordia University, Montreal, QC H4B 1R6, Canada.,Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY 14642
| | - Bjorn Bean
- Biology Department, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Jia Feng
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong, Jiangsu 226001, China
| | | | | | - Aashima Goyal
- Biology Department, Concordia University, Montreal, QC H4B 1R6, Canada
| | | | - Jaideep Mallick
- Biology Department, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Malcolm Whiteway
- Biology Department, Concordia University, Montreal, QC H4B 1R6, Canada
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25
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Matellán L, Monje-Casas F. Regulation of Mitotic Exit by Cell Cycle Checkpoints: Lessons From Saccharomyces cerevisiae. Genes (Basel) 2020; 11:E195. [PMID: 32059558 PMCID: PMC7074328 DOI: 10.3390/genes11020195] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/07/2020] [Accepted: 02/11/2020] [Indexed: 02/06/2023] Open
Abstract
In order to preserve genome integrity and their ploidy, cells must ensure that the duplicated genome has been faithfully replicated and evenly distributed before they complete their division by mitosis. To this end, cells have developed highly elaborated checkpoints that halt mitotic progression when problems in DNA integrity or chromosome segregation arise, providing them with time to fix these issues before advancing further into the cell cycle. Remarkably, exit from mitosis constitutes a key cell cycle transition that is targeted by the main mitotic checkpoints, despite these surveillance mechanisms being activated by specific intracellular signals and acting at different stages of cell division. Focusing primarily on research carried out using Saccharomyces cerevisiae as a model organism, the aim of this review is to provide a general overview of the molecular mechanisms by which the major cell cycle checkpoints control mitotic exit and to highlight the importance of the proper regulation of this process for the maintenance of genome stability during the distribution of the duplicated chromosomes between the dividing cells.
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Affiliation(s)
| | - Fernando Monje-Casas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Spanish National Research Council (CSIC)—University of Seville—University Pablo de Olavide, Avda, Américo Vespucio, 24, 41092 Sevilla, Spain;
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26
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Feng J, Shan A, Hu J, Cao Z, Lv R, Feng J. Genetic interaction between Ptc2 and protein phosphatase 4 (PP4) in the regulation of DNA damage response and virulence in Candida albicans. FEMS Yeast Res 2019; 19:5603746. [PMID: 31644792 DOI: 10.1093/femsyr/foz075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/22/2019] [Indexed: 12/13/2022] Open
Abstract
In the pathogenic fungus Candida albicans, phosphoregulation of the checkpoint kinase Rad53 plays a crucial role in the filamentous growth response to genotoxic stresses. The protein phosphatase 4 (PP4) complex, containing Pph3 and either Psy2 or Psy4, is proved to play a critical role in Rad53 dephosphorylation. In previous studies, we characterized CaPtc2 (the ortholog of both Ptc2 and Ptc3 in Saccharomyces cerevisiae) as a potential DNA-damage-related protein phosphatase. In this study, we checked the genetic interaction of PTC2 with the PP4 complex in the DNA damage response pathway. The results suggest that Ptc2 shows a negative genetic interaction with Pph3, but positive genetic interaction with either Psy2 or Psy4 in response to genotoxic stress. Deletion of PTC2 alone resulted in no significant change in cell virulence, but double deletion of PTC2 PPH3 significantly decreased virulence, while double deletions of either PTC2 PSY2 or PTC2 PSY4 caused virulence levels similar to that shown by PSY2 or PSY4 single-gene deletion cells. Taken together, we propose that Ptc2 in C. albicans plays a compensatory role for Pph3 but is dependent on Psy2 and Psy4 in regulation of DNA damage and cell virulence.
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Affiliation(s)
- Jia Feng
- Department of Pathogen Biology, School of Medicine, Nantong University, No.19 Qixiu Road, Nantong City, Jiangsu Province, Nantong 226001, China
| | - Aidi Shan
- Department of Pathogen Biology, School of Medicine, Nantong University, No.19 Qixiu Road, Nantong City, Jiangsu Province, Nantong 226001, China
| | - Jing Hu
- Department of Pathogen Biology, School of Medicine, Nantong University, No.19 Qixiu Road, Nantong City, Jiangsu Province, Nantong 226001, China
| | - Zhenyu Cao
- Department of Pathogen Biology, School of Medicine, Nantong University, No.19 Qixiu Road, Nantong City, Jiangsu Province, Nantong 226001, China
| | - Rui Lv
- Department of Pathogen Biology, School of Medicine, Nantong University, No.19 Qixiu Road, Nantong City, Jiangsu Province, Nantong 226001, China
| | - Jinrong Feng
- Department of Pathogen Biology, School of Medicine, Nantong University, No.19 Qixiu Road, Nantong City, Jiangsu Province, Nantong 226001, China
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Entrenching role of cell cycle checkpoints and autophagy for maintenance of genomic integrity. DNA Repair (Amst) 2019; 86:102748. [PMID: 31790874 DOI: 10.1016/j.dnarep.2019.102748] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/19/2019] [Accepted: 11/08/2019] [Indexed: 12/22/2022]
Abstract
Genomic integrity of the cell is crucial for the successful transmission of genetic information to the offspring and its survival. Persistent DNA damage induced by endogenous and exogenous agents leads to various metabolic manifestations. To combat this, eukaryotes have developed complex DNA damage response (DDR) pathway which senses the DNA damage and activates an arsenal of enzymes for the repair of damaged DNA. The active pathways for DNA repair are nucleotide excision repair (NER), base excision repair (BER) and mismatch repair (MMR) for single-strand break repair whereas homologous recombination (HR) and non-homologous end-joining (NHEJ) for double-strand break repair. OGG1 is a DNA glycosylase which initiates BER while Mre11-Rad50-Nbs1 (MRN) protein complex is the primary responder to DSBs which gets localized to damage sites. DNA damage response is meticulously executed by three related kinases: ATM, ATR, and DNA-PK. ATM- and ATR-dependent phosphorylation of p53, Chk1, and Chk2 regulate the G1/S, intra-S, or G2/M checkpoints of the cell cycle, respectively. Autophagy is an evolutionarily conserved process that plays a pivotal role in the regulation of DNA repair and maintains the cellular homeostasis. Genotoxic stress-induced altered autophagy occurs in a P53 dependent manner which is also the master regulator of genotoxic stress. A plethora of proteins involved in autophagy is regulated by p53 which involve DRAM, DAPK, and AMPK. As evident, the mtDNA is more prone to damage than nuclear DNA because of its close proximity to the site of ROS generation. Depending on the extent of damage either the repair mechanism or mitophagy gets triggered. SIRT1 is the master regulator which directs the stress response to mitophagy. Nix, a LC3 adapter also participates in Parkin mediated mitophagy. This review highlights the intricate crosstalks between DNA damage and cell cycle checkpoints activation. The DNA damage mediated regulation of autophagy and mitophagy is also reviewed in detail.
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Memisoglu G, Haber JE. Dephosphorylation of the Atg1 kinase complex by type 2C protein phosphatases. Mol Cell Oncol 2019; 6:1588658. [PMID: 31131308 PMCID: PMC6512942 DOI: 10.1080/23723556.2019.1588658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 02/22/2019] [Accepted: 02/26/2019] [Indexed: 11/16/2022]
Abstract
In budding yeast, Atg1 kinase, together with Atg13 and Atg17, forms a complex that is essential for autophagy. Previous work showed that the Atg1 kinase complex is regulated extensively by phosphorylations. Our recent paper demonstrates that type 2C protein phosphatases Ptc2 and Ptc3 are involved in the dephosphorylation of Atg13 and Atg1 kinase to promote autophagy.
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Affiliation(s)
- Gonen Memisoglu
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, USA.,Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, USA
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29
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Ariño J, Velázquez D, Casamayor A. Ser/Thr protein phosphatases in fungi: structure, regulation and function. MICROBIAL CELL 2019; 6:217-256. [PMID: 31114794 PMCID: PMC6506691 DOI: 10.15698/mic2019.05.677] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Reversible phospho-dephosphorylation of proteins is a major mechanism for the control of cellular functions. By large, Ser and Thr are the most frequently residues phosphorylated in eukar-yotes. Removal of phosphate from these amino acids is catalyzed by a large family of well-conserved enzymes, collectively called Ser/Thr protein phosphatases. The activity of these enzymes has an enormous impact on cellular functioning. In this work we pre-sent the members of this family in S. cerevisiae and other fungal species, and review the most recent findings concerning their regu-lation and the roles they play in the most diverse aspects of cell biology.
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Affiliation(s)
- Joaquín Ariño
- Departament de Bioquímica i Biologia Molecular and Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Diego Velázquez
- Departament de Bioquímica i Biologia Molecular and Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Antonio Casamayor
- Departament de Bioquímica i Biologia Molecular and Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
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30
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Verma N, Franchitto M, Zonfrilli A, Cialfi S, Palermo R, Talora C. DNA Damage Stress: Cui Prodest? Int J Mol Sci 2019; 20:E1073. [PMID: 30832234 PMCID: PMC6429504 DOI: 10.3390/ijms20051073] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 02/18/2019] [Accepted: 02/26/2019] [Indexed: 12/25/2022] Open
Abstract
DNA is an entity shielded by mechanisms that maintain genomic stability and are essential for living cells; however, DNA is constantly subject to assaults from the environment throughout the cellular life span, making the genome susceptible to mutation and irreparable damage. Cells are prepared to mend such events through cell death as an extrema ratio to solve those threats from a multicellular perspective. However, in cells under various stress conditions, checkpoint mechanisms are activated to allow cells to have enough time to repair the damaged DNA. In yeast, entry into the cell cycle when damage is not completely repaired represents an adaptive mechanism to cope with stressful conditions. In multicellular organisms, entry into cell cycle with damaged DNA is strictly forbidden. However, in cancer development, individual cells undergo checkpoint adaptation, in which most cells die, but some survive acquiring advantageous mutations and selfishly evolve a conflictual behavior. In this review, we focus on how, in cancer development, cells rely on checkpoint adaptation to escape DNA stress and ultimately to cell death.
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Affiliation(s)
- Nagendra Verma
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy.
| | - Matteo Franchitto
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy.
| | - Azzurra Zonfrilli
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy.
| | - Samantha Cialfi
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy.
| | - Rocco Palermo
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy.
| | - Claudio Talora
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy.
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31
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Ciardo D, Goldar A, Marheineke K. On the Interplay of the DNA Replication Program and the Intra-S Phase Checkpoint Pathway. Genes (Basel) 2019; 10:E94. [PMID: 30700024 PMCID: PMC6410103 DOI: 10.3390/genes10020094] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 01/23/2019] [Accepted: 01/25/2019] [Indexed: 12/12/2022] Open
Abstract
DNA replication in eukaryotes is achieved by the activation of multiple replication origins which needs to be precisely coordinated in space and time. This spatio-temporal replication program is regulated by many factors to maintain genome stability, which is frequently threatened through stresses of exogenous or endogenous origin. Intra-S phase checkpoints monitor the integrity of DNA synthesis and are activated when replication forks are stalled. Their activation leads to the stabilization of forks, to the delay of the replication program by the inhibition of late firing origins, and the delay of G2/M phase entry. In some cell cycles during early development these mechanisms are less efficient in order to allow rapid cell divisions. In this article, we will review our current knowledge of how the intra-S phase checkpoint regulates the replication program in budding yeast and metazoan models, including early embryos with rapid S phases. We sum up current models on how the checkpoint can inhibit origin firing in some genomic regions, but allow dormant origin activation in other regions. Finally, we discuss how numerical and theoretical models can be used to connect the multiple different actors into a global process and to extract general rules.
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Affiliation(s)
- Diletta Ciardo
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette CEDEX, France.
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32
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PP2C phosphatases promote autophagy by dephosphorylation of the Atg1 complex. Proc Natl Acad Sci U S A 2019; 116:1613-1620. [PMID: 30655342 DOI: 10.1073/pnas.1817078116] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Macroautophagy is orchestrated by the Atg1-Atg13 complex in budding yeast. Under nutrient-rich conditions, Atg13 is maintained in a hyperphosphorylated state by the TORC1 kinase. After nutrient starvation, Atg13 is dephosphorylated, triggering Atg1 kinase activity and macroautophagy induction. The phosphatases that dephosphorylate Atg13 remain uncharacterized. Here, we show that two redundant PP2C phosphatases, Ptc2 and Ptc3, regulate macroautophagy by dephosphorylating Atg13 and Atg1. In the absence of these phosphatases, starvation-induced macroautophagy and the cytoplasm-to-vacuole targeting pathway are inhibited, and the recruitment of the essential autophagy machinery to the phagophore assembly site is impaired. Expressing a genomic ATG13 -8SA allele lacking key TORC1 phosphorylation sites partially bypasses the macroautophagy defect in ptc2Δ ptc3Δ strains. Moreover, Ptc2 and Ptc3 interact with the Atg1-Atg13 complex. Taken together, these results suggest that PP2C-type phosphatases promote macroautophagy by regulating the Atg1 complex.
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33
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Lao JP, Ulrich KM, Johnson JR, Newton BW, Vashisht AA, Wohlschlegel JA, Krogan NJ, Toczyski DP. The Yeast DNA Damage Checkpoint Kinase Rad53 Targets the Exoribonuclease, Xrn1. G3 (BETHESDA, MD.) 2018; 8:3931-3944. [PMID: 30377154 PMCID: PMC6288840 DOI: 10.1534/g3.118.200767] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/15/2018] [Indexed: 12/15/2022]
Abstract
The highly conserved DNA damage response (DDR) pathway monitors the genomic integrity of the cell and protects against genotoxic stresses. The apical kinases, Mec1 and Tel1 (ATR and ATM in human, respectively), initiate the DNA damage signaling cascade through the effector kinases, Rad53 and Chk1, to regulate a variety of cellular processes including cell cycle progression, DNA damage repair, chromatin remodeling, and transcription. The DDR also regulates other cellular pathways, but direct substrates and mechanisms are still lacking. Using a mass spectrometry-based phosphoproteomic screen in Saccharomyces cerevisiae, we identified novel targets of Rad53, many of which are proteins that are involved in RNA metabolism. Of the 33 novel substrates identified, we verified that 12 are directly phosphorylated by Rad53 in vitro: Xrn1, Gcd11, Rps7b, Ded1, Cho2, Pus1, Hst1, Srv2, Set3, Snu23, Alb1, and Scp160. We further characterized Xrn1, a highly conserved 5' exoribonuclease that functions in RNA degradation and the most enriched in our phosphoproteomics screen. Phosphorylation of Xrn1 by Rad53 does not appear to affect Xrn1's intrinsic nuclease activity in vitro, but may affect its activity or specificity in vivo.
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Affiliation(s)
- Jessica P Lao
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Katie M Ulrich
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Jeffrey R Johnson
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Billy W Newton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Ajay A Vashisht
- Department of Biological Chemistry, School of Medicine, University of California, Los Angeles, CA 90095
| | - James A Wohlschlegel
- Department of Biological Chemistry, School of Medicine, University of California, Los Angeles, CA 90095
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - David P Toczyski
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
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34
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Adaptation to DNA damage checkpoint in senescent telomerase-negative cells promotes genome instability. Genes Dev 2018; 32:1499-1513. [PMID: 30463903 PMCID: PMC6295172 DOI: 10.1101/gad.318485.118] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/03/2018] [Indexed: 01/04/2023]
Abstract
Here, Coutelier et al. used a microfluidic-based approach and live-cell imaging in yeast to capture early mutation events during replicative senescence and observed that prolonged checkpoint arrests occurred frequently in telomerase-negative lineages. Their results demonstrate that the adaptation pathway is a major contributor to the genome instability induced during replicative senescence. In cells lacking telomerase, telomeres gradually shorten during each cell division to reach a critically short length, permanently activate the DNA damage checkpoint, and trigger replicative senescence. The increase in genome instability that occurs as a consequence may contribute to the early steps of tumorigenesis. However, because of the low frequency of mutations and the heterogeneity of telomere-induced senescence, the timing and mechanisms of genome instability increase remain elusive. Here, to capture early mutation events during replicative senescence, we used a combined microfluidic-based approach and live-cell imaging in yeast. We analyzed DNA damage checkpoint activation in consecutive cell divisions of individual cell lineages in telomerase-negative yeast cells and observed that prolonged checkpoint arrests occurred frequently in telomerase-negative lineages. Cells relied on the adaptation to the DNA damage pathway to bypass the prolonged checkpoint arrests, allowing further cell divisions despite the presence of unrepaired DNA damage. We demonstrate that the adaptation pathway is a major contributor to the genome instability induced during replicative senescence. Therefore, adaptation plays a critical role in shaping the dynamics of genome instability during replicative senescence.
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35
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Millan-Zambrano G, Santos-Rosa H, Puddu F, Robson SC, Jackson SP, Kouzarides T. Phosphorylation of Histone H4T80 Triggers DNA Damage Checkpoint Recovery. Mol Cell 2018; 72:625-635.e4. [PMID: 30454561 PMCID: PMC6242705 DOI: 10.1016/j.molcel.2018.09.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 08/08/2018] [Accepted: 09/18/2018] [Indexed: 11/24/2022]
Abstract
In response to genotoxic stress, cells activate a signaling cascade known as the DNA damage checkpoint (DDC) that leads to a temporary cell cycle arrest and activation of DNA repair mechanisms. Because persistent DDC activation compromises cell viability, this process must be tightly regulated. However, despite its importance, the mechanisms regulating DDC recovery are not completely understood. Here, we identify a DNA-damage-regulated histone modification in Saccharomyces cerevisiae, phosphorylation of H4 threonine 80 (H4T80ph), and show that it triggers checkpoint inactivation. H4T80ph is critical for cell survival to DNA damage, and its absence causes impaired DDC recovery and persistent cell cycle arrest. We show that, in response to genotoxic stress, p21-activated kinase Cla4 phosphorylates H4T80 to recruit Rtt107 to sites of DNA damage. Rtt107 displaces the checkpoint adaptor Rad9, thereby interrupting the checkpoint-signaling cascade. Collectively, our results indicate that H4T80ph regulates DDC recovery.
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Affiliation(s)
- Gonzalo Millan-Zambrano
- The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
| | - Helena Santos-Rosa
- The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Fabio Puddu
- The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Samuel C Robson
- School of Pharmacy and Biomedical Science, University of Portsmouth, White Swan Road, Portsmouth PO1 2DT, UK
| | - Stephen P Jackson
- The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Tony Kouzarides
- The Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
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36
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Byrne BM, Oakley GG. Replication protein A, the laxative that keeps DNA regular: The importance of RPA phosphorylation in maintaining genome stability. Semin Cell Dev Biol 2018; 86:112-120. [PMID: 29665433 DOI: 10.1016/j.semcdb.2018.04.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/30/2018] [Accepted: 04/06/2018] [Indexed: 11/25/2022]
Abstract
The eukaryotic ssDNA-binding protein, Replication protein A (RPA), was first discovered almost three decades ago. Since then, much progress has been made to elucidate the critical roles for RPA in DNA metabolic pathways that help promote genomic stability. The canonical RPA heterotrimer (RPA1-3) is an essential coordinator of DNA metabolism that interacts with ssDNA and numerous protein partners to coordinate its roles in DNA replication, repair, recombination and telomere maintenance. An alternative form of RPA, termed aRPA, is formed by a complex of RPA4 with RPA1 and RPA3. aRPA is expressed differentially in cells compared to canonical RPA and has been shown to inhibit canonical RPA function while allowing for regular maintenance of cell viability. Interestingly, while aRPA is defective in DNA replication and cell cycle progression, it was shown to play a supporting role in nucleotide excision repair and recombination. The binding domains of canonical RPA interact with a growing number of partners involved in numerous genome maintenance processes. The protein interactions of the RPA-ssDNA complex are not only governed by competition between the binding proteins but also by post-translation modifications such as phosphorylation. Phosphorylation of RPA2 is an important post-translational modification of the RPA complex, and is essential for directing context-specific functions of the RPA complex in the DNA damage response. Due to the importance of RPA in cellular metabolism, it was identified as an appealing target for chemotherapeutic drug development that could be used in future cancer treatment regimens.
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Affiliation(s)
- Brendan M Byrne
- University of Nebraska Medical Center Department of Oral Biology, Lincoln NE, USA.
| | - Gregory G Oakley
- University of Nebraska Medical Center Department of Oral Biology, Lincoln NE, USA; Eppley Cancer Center, Omaha NE, USA.
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37
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Botchkarev VV, Haber JE. Functions and regulation of the Polo-like kinase Cdc5 in the absence and presence of DNA damage. Curr Genet 2018; 64:87-96. [PMID: 28770345 PMCID: PMC6249032 DOI: 10.1007/s00294-017-0727-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 07/24/2017] [Accepted: 07/26/2017] [Indexed: 12/20/2022]
Abstract
Polo-like kinases are essential cell cycle regulators that are conserved from yeast to humans. Unlike higher eukaryotes, who express multiple Polo-like kinase family members that perform many important functions, budding yeast express only a single Polo-like kinase, Cdc5, which is the homolog of mammalian cell cycle master regulator Polo-like kinase 1. Cdc5 is a fascinating multifaceted protein that is programmed to target its many substrates in a timely, sequential manner to ensure proper cell cycle progression. Over the years, many lessons about Polo-like kinase 1 have been learned by studying Cdc5 in budding yeast. Cdc5 has been well documented in regulating mitotic entry, chromosome segregation, mitotic exit, and cytokinesis. Cdc5 also plays important roles during cell division after DNA damage. Here, we briefly review the many functions of Cdc5 and its regulation in the absence and presence of DNA damage.
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Affiliation(s)
- Vladimir V Botchkarev
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, 02454, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - James E Haber
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, 02454, USA.
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Diao LT, Chen CC, Dennehey B, Pal S, Wang P, Shen ZJ, Deem A, Tyler JK. Delineation of the role of chromatin assembly and the Rtt101Mms1 E3 ubiquitin ligase in DNA damage checkpoint recovery in budding yeast. PLoS One 2017; 12:e0180556. [PMID: 28749957 PMCID: PMC5531559 DOI: 10.1371/journal.pone.0180556] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 06/16/2017] [Indexed: 01/03/2023] Open
Abstract
The DNA damage checkpoint is activated in response to DNA double-strand breaks (DSBs). We had previously shown that chromatin assembly mediated by the histone chaperone Asf1 triggers inactivation of the DNA damage checkpoint in yeast after DSB repair, also called checkpoint recovery. Here we show that chromatin assembly factor 1 (CAF-1) also contributes to chromatin reassembly after DSB repair, explaining its role in checkpoint recovery. Towards understanding how chromatin assembly promotes checkpoint recovery, we find persistent presence of the damage sensors Ddc1 and Ddc2 after DSB repair in asf1 mutants. The genes encoding the E3 ubiquitin ligase complex Rtt101Mms1 are epistatic to ASF1 for survival following induction of a DSB, and Rtt101Mms1 are required for checkpoint recovery after DSB repair but not for chromatin assembly. By contrast, the Mms22 substrate adaptor that is degraded by Rtt101Mms1 is required for DSB repair per se. Deletion of MMS22 blocks loading of Rad51 at the DSB, while deletion of ASF1 or RTT101 leads to persistent Rad51 loading. We propose that checkpoint recovery is promoted by Rtt101Mms1-mediated ubiquitylation of Mms22 in order to halt Mms22-dependent loading of Rad51 onto double-stranded DNA after DSB repair, in concert with the chromatin assembly-mediated displacement of Rad51 and checkpoint sensors from the site of repair.
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Affiliation(s)
- Li-Ting Diao
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
| | - Chin-Chuan Chen
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas, MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Briana Dennehey
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas, MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Sangita Pal
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
| | - Pingping Wang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
| | - Zie-Jie Shen
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
| | - Angela Deem
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas, MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Jessica K. Tyler
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
- * E-mail:
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Ferrari E, Bruhn C, Peretti M, Cassani C, Carotenuto WV, Elgendy M, Shubassi G, Lucca C, Bermejo R, Varasi M, Minucci S, Longhese MP, Foiani M. PP2A Controls Genome Integrity by Integrating Nutrient-Sensing and Metabolic Pathways with the DNA Damage Response. Mol Cell 2017. [PMID: 28648781 PMCID: PMC5526790 DOI: 10.1016/j.molcel.2017.05.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mec1ATR mediates the DNA damage response (DDR), integrating chromosomal signals and mechanical stimuli. We show that the PP2A phosphatases, ceramide-activated enzymes, couple cell metabolism with the DDR. Using genomic screens, metabolic analysis, and genetic and pharmacological studies, we found that PP2A attenuates the DDR and that three metabolic circuits influence the DDR by modulating PP2A activity. Irc21, a putative cytochrome b5 reductase that promotes the condensation reaction generating dihydroceramides (DHCs), and Ppm1, a PP2A methyltransferase, counteract the DDR by activating PP2A; conversely, the nutrient-sensing TORC1-Tap42 axis sustains DDR activation by inhibiting PP2A. Loss-of-function mutations in IRC21, PPM1, and PP2A and hyperactive tap42 alleles rescue mec1 mutants. Ceramides synergize with rapamycin, a TORC1 inhibitor, in counteracting the DDR. Hence, PP2A integrates nutrient-sensing and metabolic pathways to attenuate the Mec1ATR response. Our observations imply that metabolic changes affect genome integrity and may help with exploiting therapeutic options and repositioning known drugs.
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Affiliation(s)
- Elisa Ferrari
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Christopher Bruhn
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Marta Peretti
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Corinne Cassani
- Università degli Studi di Milano-Bicocca, 20126 Milan, Italy
| | | | - Mohamed Elgendy
- Istituto Europeo di Oncologia, Via Adamello 16, 20139 Milan, Italy
| | - Ghadeer Shubassi
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Chiara Lucca
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Rodrigo Bermejo
- Centro de Investigaciones Biológicas (CIB-CSIC), 28040 Madrid, Spain
| | - Mario Varasi
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Saverio Minucci
- Istituto Europeo di Oncologia, Via Adamello 16, 20139 Milan, Italy; Università degli Studi di Milano, 20133 Milan, Italy
| | | | - Marco Foiani
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy; Università degli Studi di Milano, 20133 Milan, Italy.
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40
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Characterization of Pph3-mediated dephosphorylation of Rad53 during methyl methanesulfonate-induced DNA damage repair in Candida albicans. Biochem J 2017; 474:1293-1306. [DOI: 10.1042/bcj20160889] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 10/28/2016] [Accepted: 02/08/2017] [Indexed: 12/23/2022]
Abstract
Genotoxic stress causes DNA damage or stalled DNA replication and filamentous growth in the pathogenic fungus Candida albicans. The DNA checkpoint kinase Rad53 critically regulates by phosphorylation effectors that execute the stress response. Rad53 itself is activated by phosphorylation and inactivated by dephosphorylation. Previous studies have suggested that the phosphatase Pph3 dephosphorylates Rad53. Here, we used mass spectrometry and mutagenesis to identify Pph3 dephosphorylation sites on Rad53 in C. albicans. We found that serine residues 351, 461 and 477, which were dephosphorylated in wild-type cells during the recovery from DNA damage caused by methyl methanesulfonate (MMS), remained phosphorylated in pph3Δ/Δ cells. Phosphomimetic mutation of the three residues (rad53-3D) impaired Rad53 dephosphorylation, exit from cell cycle arrest, dephosphorylation of two Rad53 effectors Dun1 and Dbf4, and the filament-to-yeast growth transition during the recovery from MMS-induced DNA damage. The phenotypes observed in the rad53-3D mutant also occurred in the pph3Δ/Δ mutant. Together, our findings reveal a molecular mechanism by which Pph3 controls DNA damage response in C. albicans.
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Tsabar M, Waterman DP, Aguilar F, Katsnelson L, Eapen VV, Memisoglu G, Haber JE. Asf1 facilitates dephosphorylation of Rad53 after DNA double-strand break repair. Genes Dev 2017; 30:1211-24. [PMID: 27222517 PMCID: PMC4888841 DOI: 10.1101/gad.280685.116] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 04/29/2016] [Indexed: 02/07/2023]
Abstract
In this study, Tsabar et al. investigated how the DNA damage checkpoint is extinguished and found that dissociation of histone H3 from Asf1, a histone chaperone, is required for efficient recovery. They also show that Asf1 is required for complete dephosphorylation of Rad53 when the upstream DNA damage checkpoint signaling is turned off, providing new insights into the mechanisms regulating the response to DNA damage. To allow for sufficient time to repair DNA double-stranded breaks (DSBs), eukaryotic cells activate the DNA damage checkpoint. In budding yeast, Rad53 (mammalian Chk2) phosphorylation parallels the persistence of the unrepaired DSB and is extinguished when repair is complete in a process termed recovery or when the cells adapt to the DNA damage checkpoint. A strain containing a slowly repaired DSB does not require the histone chaperone Asf1 to resume cell cycle progression after DSB repair. When a second, rapidly repairable DSB is added to this strain, Asf1 becomes required for recovery. Recovery from two repairable DSBs also depends on the histone acetyltransferase Rtt109 and the cullin subunit Rtt101, both of which modify histone H3 that is associated with Asf1. We show that dissociation of histone H3 from Asf1 is required for efficient recovery and that Asf1 is required for complete dephosphorylation of Rad53 when the upstream DNA damage checkpoint signaling is turned off. Our data suggest that the requirements for recovery from the DNA damage checkpoint become more stringent with increased levels of damage and that Asf1 plays a histone chaperone-independent role in facilitating complete Rad53 dephosphorylation following repair.
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Affiliation(s)
- Michael Tsabar
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - David P Waterman
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Fiona Aguilar
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Lizabeth Katsnelson
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Vinay V Eapen
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Gonen Memisoglu
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - James E Haber
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
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Mehta A, Beach A, Haber JE. Homology Requirements and Competition between Gene Conversion and Break-Induced Replication during Double-Strand Break Repair. Mol Cell 2017; 65:515-526.e3. [PMID: 28065599 DOI: 10.1016/j.molcel.2016.12.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/27/2016] [Accepted: 12/01/2016] [Indexed: 11/27/2022]
Abstract
Saccharomyces cerevisiae mating-type switching is initiated by a double-strand break (DSB) at MATa, leaving one cut end perfectly homologous to the HMLα donor, while the second end must be processed to remove a non-homologous tail before completing repair by gene conversion (GC). When homology at the matched end is ≤150 bp, efficient repair depends on the recombination enhancer, which tethers HMLα near the DSB. Thus, homology shorter than an apparent minimum efficient processing segment can be rescued by tethering the donor near the break. When homology at the second end is ≤150 bp, second-end capture becomes inefficient and repair shifts from GC to break-induced replication (BIR). But when pol32 or pif1 mutants block BIR, GC increases 3-fold, indicating that the steps blocked by these mutations are reversible. With short second-end homology, absence of the RecQ helicase Sgs1 promotes gene conversion, whereas deletion of the FANCM-related Mph1 helicase promotes BIR.
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Affiliation(s)
- Anuja Mehta
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Annette Beach
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA.
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Recovery from the DNA Replication Checkpoint. Genes (Basel) 2016; 7:genes7110094. [PMID: 27801838 PMCID: PMC5126780 DOI: 10.3390/genes7110094] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 10/20/2016] [Accepted: 10/23/2016] [Indexed: 11/17/2022] Open
Abstract
Checkpoint recovery is integral to a successful checkpoint response. Checkpoint pathways monitor progress during cell division so that in the event of an error, the checkpoint is activated to block the cell cycle and activate repair pathways. Intrinsic to this process is that once repair has been achieved, the checkpoint signaling pathway is inactivated and cell cycle progression resumes. We use the term “checkpoint recovery” to describe the pathways responsible for the inactivation of checkpoint signaling and cell cycle re-entry after the initial stress has been alleviated. The DNA replication or S-phase checkpoint monitors the integrity of DNA synthesis. When replication stress is encountered, replication forks are stalled, and the checkpoint signaling pathway is activated. Central to recovery from the S-phase checkpoint is the restart of stalled replication forks. If checkpoint recovery fails, stalled forks may become unstable and lead to DNA breaks or unusual DNA structures that are difficult to resolve, causing genomic instability. Alternatively, if cell cycle resumption mechanisms become uncoupled from checkpoint inactivation, cells with under-replicated DNA might proceed through the cell cycle, also diminishing genomic stability. In this review, we discuss the molecular mechanisms that contribute to inactivation of the S-phase checkpoint signaling pathway and the restart of replication forks during recovery from replication stress.
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Abstract
Double-strand breaks (DSBs) pose a severe challenge to genome integrity; consequently, cells have developed efficient mechanisms to repair DSBs through several pathways of homologous recombination and other nonhomologous end-joining processes. Much of our understanding of these pathways has come from the analysis of site-specific DSBs created by the HO endonuclease in the budding yeast Saccharomyces cerevisiae. I was fortunate to get in on the ground floor of analyzing the fate of synchronously induced DSBs through the study of what I coined "in vivo biochemistry." I have had the remarkable good fortune to profit from the development of new techniques that have permitted an ever more detailed dissection of these repair mechanisms, which are described here.
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Affiliation(s)
- James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02453;
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Mersaoui SY, Gravel S, Karpov V, Wellinger RJ. DNA damage checkpoint adaptation genes are required for division of cells harbouring eroded telomeres. MICROBIAL CELL 2015; 2:394-405. [PMID: 28357265 PMCID: PMC5354583 DOI: 10.15698/mic2015.10.229] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In budding yeast, telomerase and the Cdc13p protein are two key players acting to ensure telomere stability. In the absence of telomerase, cells eventually enter a growth arrest which only few can overcome via a conserved process; such cells are called survivors. Survivors rely on homologous recombination-dependent mechanisms for telomeric repeat addition. Previously, we showed that such survivor cells also manage to bypass the loss of the essential Cdc13p protein to give rise to Cdc13-independent (or cap-independent) strains. Here we show that Cdc13-independent cells grow with persistently recognized DNA damage, which does not however result in a checkpoint activation; thus no defect in cell cycle progression is detectable. The absence of checkpoint signalling rather is due to the accumulation of mutations in checkpoint genes such as RAD24 or MEC1. Importantly, our results also show that cells that have lost the ability to adapt to persistent DNA damage, also are very much impaired in generating cap-independent cells. Altogether, these results show that while the capping process can be flexible, it takes a very specific genetic setup to allow a change from canonical capping to alternative capping. We hypothesize that in the alternative capping mode, genome integrity mechanisms are abrogated, which could cause increased mutation frequencies. These results from yeast have clear parallels in transformed human cancer cells and offer deeper insights into processes operating in pre-cancerous human cells that harbour eroded telomeres.
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Affiliation(s)
- Sofiane Y Mersaoui
- Dept of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, J1E 4K8, Canada
| | - Serge Gravel
- Dept of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, J1E 4K8, Canada
| | - Victor Karpov
- Dept of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, J1E 4K8, Canada
| | - Raymund J Wellinger
- Dept of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3201, Rue Jean Mignault, Sherbrooke, J1E 4K8, Canada
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Termination of Replication Stress Signaling via Concerted Action of the Slx4 Scaffold and the PP4 Phosphatase. Genetics 2015; 201:937-49. [PMID: 26362319 DOI: 10.1534/genetics.115.181479] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/09/2015] [Indexed: 12/22/2022] Open
Abstract
In response to replication stress, signaling mediated by DNA damage checkpoint kinases protects genome integrity. However, following repair or bypass of DNA lesions, checkpoint signaling needs to be terminated for continued cell cycle progression and proliferation. In budding yeast, the PP4 phosphatase has been shown to play a key role in preventing hyperactivation of the checkpoint kinase Rad53. In addition, we recently uncovered a phosphatase-independent mechanism for downregulating Rad53 in which the DNA repair scaffold Slx4 decreases engagement of the checkpoint adaptor Rad9 at DNA lesions. Here we reveal that proper termination of checkpoint signaling following the bypass of replication blocks imposed by alkylated DNA adducts requires the concerted action of these two fundamentally distinct mechanisms of checkpoint downregulation. Cells lacking both SLX4 and the PP4-subunit PPH3 display a synergistic increase in Rad53 signaling and are exquisitely sensitive to the DNA alkylating agent methyl methanesulfonate, which induces replication blocks and extensive formation of chromosomal linkages due to template switching mechanisms required for fork bypass. Rad53 hypersignaling in these cells seems to converge to a strong repression of Mus81-Mms4, the endonuclease complex responsible for resolving chromosomal linkages, thus explaining the selective sensitivity of slx4Δ pph3Δ cells to alkylation damage. Our results support a model in which Slx4 acts locally to downregulate Rad53 activation following fork bypass, while PP4 acts on pools of active Rad53 that have diffused from the site of lesions. We propose that the proper spatial coordination of the Slx4 scaffold and PP4 action is crucial to allow timely activation of Mus81-Mms4 and, therefore, proper chromosome segregation.
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Tryptophan-Dependent Control of Colony Formation After DNA Damage via Sea3-Regulated TORC1 Signaling in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2015; 5:1379-89. [PMID: 25943524 PMCID: PMC4502372 DOI: 10.1534/g3.115.018721] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Saccharomyces cerevisiaeIml1 complex inhibits TORC1 signaling and SEACAT antagonizes the Iml1 complex. Conditions in which SEACAT functions to inhibit Iml1 and, hence, TORC1 signaling, remain largely unknown. The SEACAT member Sea3 was linked previously to telomere maintenance and DNA repair via genome-wide genetic and physical interaction studies. Therefore, we questioned whether Sea3 functioned through TORC1 to influence these pathways. Deletion of SEA3 delayed the emergence of telomerase-independent survivors that use break-induced replication (BIR) to maintain their telomeres. Similarly, sea3∆ mutants exhibited a delay in colony formation in a BIR assay strain after double-strand break (DSB) induction as well as on the DNA-damaging agent bleomycin. Deletion of IML1 rescued the impaired growth of sea3∆ mutants after DNA damage, consistent with Sea3 functioning as a regulator of TORC1 signaling. The delay was not attributable to slowed DSB repair or termination of the DNA damage checkpoint but to tryptophan auxotrophy. High levels of tryptophan in yeast peptone dextrose media did not rescue the delay in colony formation, suggesting a defect in tryptophan import, although levels of the high-affinity tryptophan permease Tat2 were not perturbed in the sea3Δ mutant. Addition of quinolinic acid, an intermediate of the de novo NAD+ biosynthetic pathway, however, rescued the delay in colony formation in the sea3Δ mutant. Together, these findings highlight the importance of enforcement of TORC1 signaling and suggest that internal tryptophan levels influence growth recovery post DNA damage through the role of tryptophan in NAD+ synthesis.
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Hustedt N, Seeber A, Sack R, Tsai-Pflugfelder M, Bhullar B, Vlaming H, van Leeuwen F, Guénolé A, van Attikum H, Srivas R, Ideker T, Shimada K, Gasser SM. Yeast PP4 interacts with ATR homolog Ddc2-Mec1 and regulates checkpoint signaling. Mol Cell 2015; 57:273-89. [PMID: 25533186 PMCID: PMC5706562 DOI: 10.1016/j.molcel.2014.11.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 10/16/2014] [Accepted: 11/14/2014] [Indexed: 12/25/2022]
Abstract
Mec1-Ddc2 (ATR-ATRIP) controls the DNA damage checkpoint and shows differential cell-cycle regulation in yeast. To find regulators of Mec1-Ddc2, we exploited a mec1 mutant that retains catalytic activity in G2 and recruitment to stalled replication forks, but which is compromised for the intra-S phase checkpoint. Two screens, one for spontaneous survivors and an E-MAP screen for synthetic growth effects, identified loss of PP4 phosphatase, pph3Δ and psy2Δ, as the strongest suppressors of mec1-100 lethality on HU. Restored Rad53 phosphorylation accounts for part, but not all, of the pph3Δ-mediated survival. Phosphoproteomic analysis confirmed that 94% of the mec1-100-compromised targets on HU are PP4 regulated, including a phosphoacceptor site within Mec1 itself, mutation of which confers damage sensitivity. Physical interaction between Pph3 and Mec1, mediated by cofactors Psy2 and Ddc2, is shown biochemically and through FRET in subnuclear repair foci. This establishes a physical and functional Mec1-PP4 unit for regulating the checkpoint response.
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Affiliation(s)
- Nicole Hustedt
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; Faculty of Sciences, University of Basel, 4056 Basel, Switzerland
| | - Andrew Seeber
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; Faculty of Sciences, University of Basel, 4056 Basel, Switzerland
| | - Ragna Sack
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Monika Tsai-Pflugfelder
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Bhupinder Bhullar
- Novartis Institutes for Biomedical Research, Novartis Pharma AG, Fabrikstrasse 22, 4056 Basel, Switzerland
| | - Hanneke Vlaming
- Division of Gene Regulation, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Fred van Leeuwen
- Division of Gene Regulation, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Aude Guénolé
- Department of Toxicogenetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, the Netherlands
| | - Haico van Attikum
- Department of Toxicogenetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, the Netherlands
| | - Rohith Srivas
- Departments of Bioengineering and Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Trey Ideker
- Departments of Bioengineering and Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kenji Shimada
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; Faculty of Sciences, University of Basel, 4056 Basel, Switzerland.
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Meurisse J, Bacquin A, Richet N, Charbonnier JB, Ochsenbein F, Peyroche A. Hug1 is an intrinsically disordered protein that inhibits ribonucleotide reductase activity by directly binding Rnr2 subunit. Nucleic Acids Res 2014; 42:13174-85. [PMID: 25378334 PMCID: PMC4245953 DOI: 10.1093/nar/gku1095] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Rad53 is a conserved protein kinase with a central role in DNA damage response and nucleotide metabolism. We observed that the expression of a dominant-lethal form of RAD53 leads to significant expression changes for at least 16 genes, including the RNR3 and the HUG1 genes, both of which are involved in the control of nucleotide metabolism. We established by multiple biophysical and biochemical approaches that Hug1 is an intrinsically disordered protein that directly binds to the small RNR subunit Rnr2. We characterized the surface of interaction involved in Hug1 binding to Rnr2, and we thus defined a new binding region to Rnr2. Moreover, we show that Hug1 is deleterious to cell growth in the context of reduced RNR activity. This inhibitory effect of Hug1 on RNR activity depends on the binding of Hug1 to Rnr2. We propose a model in which Hug1 modulates Rnr2-Rnr1 association by binding Rnr2. We show that Hug1 accumulates under various physiological conditions of high RNR induction. Hence, both the regulation and the mode of action of Hug1 are different from those of the small protein inhibitors Dif1 and Sml1, and Hug1 can be considered as a regulator for fine-tuning of RNR activity.
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Affiliation(s)
- Julie Meurisse
- CEA, iBiTecS, SBIGeM, Gif-sur-Yvette, F-91191, France CNRS-Université Paris Sud, FRE 3377, Gif-sur-Yvette, F-91191, France
| | - Agathe Bacquin
- CEA, iBiTecS, SBIGeM, Gif-sur-Yvette, F-91191, France CNRS-Université Paris Sud, FRE 3377, Gif-sur-Yvette, F-91191, France
| | - Nicolas Richet
- CEA, iBiTecS, SBSM, Laboratoire de Biologie Structurale et Radiobiologie, Gif-sur-Yvette, F-91191, France CNRS, UMR8221, Gif-sur-Yvette, F-91191, France
| | - Jean-Baptiste Charbonnier
- CEA, iBiTecS, SBSM, Laboratoire de Biologie Structurale et Radiobiologie, Gif-sur-Yvette, F-91191, France CNRS, UMR8221, Gif-sur-Yvette, F-91191, France
| | - Françoise Ochsenbein
- CEA, iBiTecS, SBSM, Laboratoire de Biologie Structurale et Radiobiologie, Gif-sur-Yvette, F-91191, France CNRS, UMR8221, Gif-sur-Yvette, F-91191, France
| | - Anne Peyroche
- CEA, iBiTecS, SBIGeM, Gif-sur-Yvette, F-91191, France CNRS-Université Paris Sud, FRE 3377, Gif-sur-Yvette, F-91191, France
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50
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Klermund J, Bender K, Luke B. High nutrient levels and TORC1 activity reduce cell viability following prolonged telomere dysfunction and cell cycle arrest. Cell Rep 2014; 9:324-335. [PMID: 25263563 DOI: 10.1016/j.celrep.2014.08.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 08/08/2014] [Accepted: 08/22/2014] [Indexed: 12/13/2022] Open
Abstract
Cells challenged with DNA damage activate checkpoints to arrest the cell cycle and allow time for repair. Successful repair coupled to subsequent checkpoint inactivation is referred to as recovery. When DNA damage cannot be repaired, a choice between permanent arrest and cycling in the presence of damage (checkpoint adaptation) must be made. While permanent arrest jeopardizes future lineages, continued proliferation is associated with the risk of genome instability. We demonstrate that nutritional signaling through target of rapamycin complex 1 (TORC1) influences the outcome of this decision. Rapamycin-mediated TORC1 inhibition prevents checkpoint adaptation via both Cdc5 inactivation and autophagy induction. Preventing adaptation results in increased cell viability and hence proliferative potential. In accordance, the ability of rapamycin to increase longevity is dependent upon the DNA damage checkpoint. The crosstalk between TORC1 and the DNA damage checkpoint may have important implications in terms of therapeutic alternatives for diseases associated with genome instability.
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Affiliation(s)
- Julia Klermund
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Katharina Bender
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Brian Luke
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany.
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